1. Field of the Invention
The present invention relates to a screen printing apparatus, and more particularly to a screen printing apparatus which is structured such that a printing agent can be applied to one plate to be printed by one apparatus so as to have different thicknesses.
2. Description of the Prior Art
For example, when bonding a conductive body to a printed circuit board, it is necessary to thinly apply a printing agent to a narrow or small conductive body and thickly apply the printing agent to a thick or wide conductive body.
Then, in the case of applying the printing agent to one printed circuit board at different thicknesses, the printing agent application is conventionally performed by two apparatuses in two independent stages. That is, at first, the printing agent is thinly applied by a first apparatus and next, is thickly applied by a second apparatus, and vice versa.
However, in the case that two apparatuses having quite the same structure are used, a lot of cost is required and a placing space is necessarily increased.
The present invention is made by taking the points mentioned above into consideration, and an object of the present invention is to provide a screen printing apparatus which is structured such that a printing agent can be applied to one plate to be printed by one apparatus so as to have different thicknesses.
Then, in accordance with a gist of the present invention, there is provided a screen printing apparatus comprising:
a mask having a width corresponding to two plates to be printed and structured such that a thickness of a portion applying a first printing to the plate to be printed is reduced by recessing the upper surface of the portion to a desired depth, screen holes are provided in the portion in accordance with a desired pattern, screen holes are provided in a portion opposite to the portion in accordance with a different pattern from that of the first said screen holes, and a recess for preventing a printing agent applied by the screen holes provided in a side to which the first printing is applied from being attached is provided in a lower surface; and
a squeegee separated into a portion moving along the portion of the mask in the side to which the first printing is to be applied, and a portion moving along the opposite portion, having different heights and integrally moving both of the portions,
with respect to one plate to be printed, after a printing is applied with the portion of the mask in the side to which the first printing is to be applied, a printing is applied to the other side.